* 1.9B - Added a bunch of changes and features.
*
* Changes: (1) Potential speed increases by using bzero(), memset(),
* and memcpy() instead of loops. (Is this really faster? I haven't
* tested it.) (2) added instructions below for compiling on Mac
* OSX. (3) Some code reshuffling, e.g. moved cell execution loop to
* executeCell() function. (4) Removed "facing" variable; cell now
* gets direction from register.
*
* These new "features" can be turned off by unsetting USE_EXTRAS: (1)
* New keyboard inputs and display settings, e.g. =/- increase/
* decrease avg. energy input. (2) Ability to save/read current run
* to/from a file, and do screenshots to a BMP file. (3) Inserting a
* genome into a cell (by typing in a string) (4) New display modes:
* LOGO and ENERGY (ENERGY is not working correctly - I want it to
* eventually be a greyscale). (5) Replaced TURN command with EJECT,
* eject output buffer into neighbor, potentially at a non-zero genome
* location (could allow for parasite/viral/sexual types of
* behavior). (6) Can add/remove "barriers" to divide the landscape
* (contintental drift!) (7) 4 STOPs in a row are required for ending
* execution (changed from one; thus it can also act as a NOP). (8)
* In-place mutations of individual living cells, in addition to
* replacement with random genomes.